Objects - HeapsIO/heaps GitHub Wiki

Object

Like shown previously in the introduction to give our Heaps application visual (2D) content we need classes that are build upon h2d.Object.

  • An Object (represented by h2d.Object) is the base class of all 2D objects, so any thing that you can add to the screen (so to a h2d.Scene to be more precise, which mainly is s2d when inside hxd.App).

  • h2d.Object provides variables like a position (x,y), a scale (scaleX,scaleY), a rotation and methods to change them.

  • However the class itself is only a container and has nothing to render by itself. For instance h2d.Flow, h2d.Layers and h2d.Mask are all "invisible", too, by that sense. Their job is to structure in which order their children objects are rendered. (See more about Object trees)

  • A sub-class that does rendering however is h2d.Drawable. These objects are the base for any actually visible objects in the world of the game like for instance the player, enemies, buildings, the landscape, but furthermore also buttons (h2d.Interactive) or a h2d.Text. (See more on Drawable)


These are all h2d package classes (and sub-classes) that extend h2d.Object and can be used to create 2D content:

  • Console
  • Drawable
    • Anim, Bitmap, Particles, SpriteBatch
    • Graphics
      • Benchmark
    • Interactive
      • Slider
    • Text
      • HtmlText, TextInput
    • TileGroup
      • ScaleGrid
    • Video
  • Flow
    • CheckBox, Dropdown
  • Mask
    • KeyFrames
  • Layers
    • CdbLevel, Scene, ZGroup
  • ObjectFollower
  • Loader

Creating and adding Objects

Objects can be added to a scene directly (a h2d.Scene, for instance s2d when inside hxd.App) or be added to another h2d.Object creating an object tree. Object trees are regarded in the next section about Object trees.

var a = new h2d.Object();              // object not added yet
s2d.addChild(a);                       // now adding `a` to `s2d` (the currently active 2D scene)

var b = new h2d.Object( s2d );         // `b` is added directly via constructor to `s2d`
b.x = 100;

var c = new h2d.Object( b );           // `c` is added to `b` which has been added to a scene (`s2d`)
c.x = 10;                              // relative to parent `b`

trace( c.getAbsPos().getPosition() );  // the absolute x-position of `c` will be 110, because it "travels" along with its parent `b`